Well, it would help if for one of these murders the spouse (killer) wasn't having an affair. Usually that is the first clue.
We have a disastrous marriage, two spouses that are fooling around elsewhere because they cut sex out of their married lives, divorce discussions and murder. Brad's affair was not something he was sneaking around doing, but rather something that was in the open for 7 months before the murder. I find it hard to connect the affair to the murder.